You're about to push SMS to Vietnam and legal mentions Decree 91/2020. Don't memorize every clause — just remember the 5 actions most often rejected. Hit one and your campaign stalls, or worse, your sender ID gets locked.
Pitfall 1: Night sending window
- Promo only 8:00-22:00; OTP/transactional can go off-hours.
- Don't use one Brandname for both OTP and midnight promos — night promos get rejected.
- Split lines: OTP/service on a separate ID, marketing strictly on the business-hours ID.
Pitfall 2: Missing opt-out
- Every promo SMS must carry an opt-out (e.g. 'Reply TD to stop').
- Missing it is a clear violation — low approval rate.
- Put opt-out at the template footer, fixed format, don't hide it.
Pitfall 3: Template/landing mismatch
- SMS says '30% off' but landing says '20% off' → rejected.
- Brand name on SMS and on the site must match.
- Get the template approved, then send — don't alter content after approval.
Pitfall 4: Unregistered Brandname
- Vietnam Brandname requires pre-registering the brand with carriers before sending.
- Using an unapproved Brandname → message blocked or falls back to an anonymous number.
- Plan registration 1-2 weeks before launch.
Pitfall 5: Complaint rate over threshold
- High complaint/spam rate gets the sender ID throttled or permanently locked.
- Send to the right people, at a sane frequency, with clear opt-out.
- Watch the negative-feedback rate; over threshold, stop and scrub the list.
Decree 91 isn't there to scare you — it's to split your lines right. OTP, service, marketing — each its own ID, each its own rule.
FAQ
What is cross-border SMS and how does it differ from domestic SMS?
Cross-border SMS is sent via foreign carriers (Vietnam, Thailand, Indonesia…) to users worldwide; it differs from domestic SMS in routes, Sender ID, and per-country compliance.
Why is my SMS template rejected and how to fix it?
Usually sensitive words, wrong format, or unregistered Sender ID. Fix: use neutral wording, follow each country's template rules, register the brandname in advance.
Should I choose Brandname, OTP, or P2P SMS?
Brandname for branded marketing/notifications; OTP for verification codes; P2P for 1-to-1 chat. Choose by use case and delivery rate.
How are delivery rate (DLR) and pricing calculated?
Billed on DLR-confirmed successful sends; failed submissions are free. Look at actual delivery rate, not just submit volume.